NP203 transfer case availability and rebuild

[90Supurban]

Hello,

I guess that I am an oddball in that I am looking FOR a NP203 while many want to swap out or convert to part time. It seems that there are rebuild kits available but not much for chains. I finally found this place that sells them for a hefty price.

NP 203 Transfer Case Chain ONLY Made in USA! HV-005

NP 203 Transfer Case Chain ONLY Made in USA! NP203 chevy chevrolet gm gmc

bjsoffroad.com

Does anyone have any experience with them?

I am looking to put the 203 behind a 4L80, and it is my understanding that the 203’s used behind a TH400 had a 32 spline input shaft. ORD sells the input shaft for $175 if needed, and Northwestfab makes a 203 to GM 6 bolt round adapter, which I think is what is needed, another $200. Then linkage and driveshafts of course.

I had a ‘79 1/2 ton pickup about 20 years ago with the 203 and I loved it for both street and off road. Worked just like the newer Denalis and Escalades with the open diff, but with the ability to lock it up for off road.

 

[nvrenuf]

400/203 combos were 32 spline but these are pretty rare compared to the extremely common 27 spline 350/203. The 32 spline units are popular for Doubler applications so they have some demand whereas the 27 spline versions are considered junk.

Research the required trans tailshaft length, the 400/203 uses an extremely short tailshaft compared to other versions.

I’d bet ORD has chain kits available but they’re probably not on their website.

 

[90Supurban]

Thank you for the info!

I’m fine with having to swap the input gear if I find a 27 spline version, as I would definitely be going through the whole case anyways. Mostly concerned about part availability on a now-45+ year old assembly.

Now, on to finding one within reasonable driving distance, that has not been sitting behind a barn buried in mud for decades, lol

 

[Old Guy Bill]

The 32 spline input gear also has a bigger bearing that means the case has to be bored for the larger bearing also… it’s not a tough job for an experienced machinist but another cost involved.
I spoke with that retailer when I thought about rebuilding my 203, they didn’t have the chains in stock and had no estimated time when they might as there is no demand for them.
I decided on going with a 208, it meant different drive shafts but a lot more options available for it. A 241 with right hand drop would be preferred but they are rare.

 

[nvrenuf]

@Old Guy Bill it’s been a while but I’m 99% sure that all of the GM versions of the 203 use the same input shaft bearing.

The 205’s use a larger input shaft bearing for 32 spline units.

 

[Old Guy Bill]

@Old Guy Bill it’s been a while but I’m 99% sure that all of the GM versions of the 203 use the same input shaft bearing.

The 205’s use a larger input shaft bearing for 32 spline units.

Yes, you are exactly correct, I wasn’t thinking clearly… damn that’s happening more lately

 

[Turbo4whl]

I found this site for some parts. I have not bought from them, but there is a phone number:

CLICK HERE

 

[Old Guy Bill]

There’s been a couple for sale on FB Market Place where I’m located, they’ve been up for a long while, both asking too much in my opinion.

 

[geardaddy]

Hello,

I guess that I am an oddball in that I am looking FOR a NP203 while many want to swap out or convert to part time. It seems that there are rebuild kits available but not much for chains. I finally found this place that sells them for a hefty price.

NP 203 Transfer Case Chain ONLY Made in USA! HV-005

NP 203 Transfer Case Chain ONLY Made in USA! NP203 chevy chevrolet gm gmc

bjsoffroad.com

Does anyone have any experience with them?

I am looking to put the 203 behind a 4L80, and it is my understanding that the 203’s used behind a TH400 had a 32 spline input shaft. ORD sells the input shaft for $175 if needed, and Northwestfab makes a 203 to GM 6 bolt round adapter, which I think is what is needed, another $200. Then linkage and driveshafts of course.

I had a ‘79 1/2 ton pickup about 20 years ago with the 203 and I loved it for both street and off road. Worked just like the newer Denalis and Escalades with the open diff, but with the ability to lock it up for off road.

I have ALOT of np203 parts, new takeouts and very nice used........sixonetwo-309-three999

 

[chasw44]

sorry to intrude but this has me wondering what the 'full time' tranny and transfer is labeled in a 79 k5 parts truck I have are. I know its a 400 sbc because thats what I bought it for but it is a auto with what I think was called quadratrac. I thought just by looking at it when I borrowed the 308 12 bolt for my 86 till I could build a 342 for it that it was a 400 with a "big xfer case", because I have never tore up a xfer case or rebuilt one my only experience was when I cobbled up the parts for a 400 with a 205 for the sbc in my 63 jeep j200 a long time ago. Also the 79 does not have the hubs you turn so the full time name stuck with me. I do have several scouts with I think all gear drive xfer cases but they are probably ih only applications and maybe not for chevy applications. Maybe jeep though as they share axles. I probably should get on a scout forum about that stuff.